This invention relates to a method and a system for processing molten slag and eventually for producing solidified slag which can be used as a construction material instead of natural gravel or the like.
Conventionally the slag which is discharged in great quantity from the refinery processes of a steel making plant is merely air-cooled so that the slag dusts or collapses or produces the yellow colored water which contains sulfur and hydrogen sulfide all of which lead to environmental pollution.
The conventional method for processing molten slag is called the "field method" wherein the molten slag is extensively spread onto a field and is air cooled for a long period. This method, however, has required a lengthy series of operations. Furthermore the solidified slag cuts deeply into the field or ground so that the thickness of the layer of the spread slag becomes irregular whereby the removing operation that is usually conducted after the slag has completely solidified becomes extremely difficult and produces a tremendous amount of dust leading to air pollution. The processed slag which is produced by this conventional method still contains the non-reacted lime or an unstable phosphorus material therein so that the slag collapses and the above mentioned yellow colored water is produced which necessitate difficult methods of treatment.
For the purpose of resolving the problems which afflict conventional methods, various improvements have been made wherein the slag in the molten stage is rapidly cooled by a desired means in order to prevent the occurrence of collapse of the slag and the production of yellow collored water.
The inventors of this application also have applied for a patent on a method for processing molten slag in Japan wherein the slag in the molten stage is spread extensively on a steel plate. However, the improved methods including the above mentioned inventors' method have proved unsuccessful from the practical point of view and have included various problems yet to be resolved.
It is an object of the present invention to provide a method and a system which can resolve the aforementioned defects of conventional methods and systems.
It is another object of the present invention to provide a method and system for processing molten slag which is characterized in that molten slag is first discharged onto the desired slag receiving means in a roofed slag processing factory and then is air and water cooled and finally is water-quenched so that the solidified slag of practical use which neither collapses nor produces dust.
It is still another object of the present invention to provide a method and a system for processing molten slag in a roofed slag processing factory without causing air pollution.
It is further an object of the present invention to provide a method and a system for processing molten slag which is characterized in that all the necessary devices for processing molten slag are arranged in a roofed slag processing factory systematically and compactly.